CHAPTER SYNOPSIS

When performing a total knee arthroplasty, it is likely that the surgeon may encounter a dilemma, potential crisis, or other unexpected obstacle. There are many pitfalls that can occur during total knee arthroplasty and in the immediate postoperative period. This chapter will address such problems and offer potential solutions for each.

IMPORTANT POINTS:

• 1
  

  Surgical incision(s)

  
  
• 2
  

  Skin necrosis

  
  
• 3
  

  Draining wounds

  
  
• 4
  

  Excessive drainage following surgery

  
  
• 5
  

  Treating large hematomas

  
  
• 6
  

  Patellar tendon avulsion

  
  
• 7
  

  Medial collateral ligament injury issues

  
  
• 8
  

  Popliteus impingement issues

  
  
• 9
  

  Size discrepancies

  
  
• 10
  

  Vascular compromise

CLINICAL/SURGICAL PEARLS:

• 1
  

  It is important that the surgeon have techniques in his or her armamentarium to address the handling of all of these issues both during the operation as well as postoperatively to diagnose and treat these issues.

CLINICAL/SURGICAL PITFALLS:

• 1
  

  The key to prevention of intraoperative complications is to anticipate their possibility and be able to recognize their presence when treating a total knee arthroplasty patient.

VIDEO AVAILABLE:

Not available.

HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM

When performing a total knee arthroplasty (TKA), it is likely that the surgeon will encounter a dilemma, potential crisis, or other unexpected obstacles. It is obvious that the recognition of any complication as well as the ability to address and treat it is paramount for an orthopedic surgeon. When addressing a TKA patient, there is a subset of specific concerns that a surgeon must consider. This chapter will address such problems and offer potential solutions for each.

SURGICAL INCISION

Following TKA, wound necrosis can sometimes follow. When this does occur, the wound necrosis can be a minor inconvenience or can lead to a major crisis, such as a secondary infection, and the potential loss of the knee arthroplasty. Choosing the right incision is of primary importance and many factors must be taken into consideration; most important is the location of prior incisions. Incisions from previous surgical procedures greatly increase the risk for wound necrosis, as necrosis of the wound is most likely to occur in these areas; therefore, respect for prior incisions is imperative. The knee, unlike the hip, does not tolerate parallel incisions or incisions that cross one another ( Fig. 13-1 ). Ideally, the skin incision for an uncompromised knee is vertical and reasonably straight. The incision should be 10 to 15 cm long, begin over the distal aspect of the femur, cross the medial third of the patella, and complete itself just medial to the tibial tubercle. Incisions encountered from surgical procedures that occurred during the 1970s will likely be parapatellar with curvature around the medial border of the patella creating a lateral skin flap. Many times, this type of incision led to necrosis at the apex of the flap; therefore, the change to straight incisions occurred over the years. Evidence has shown that the vascular supply of the skin in this area is much more tolerant of a medially based flap, as opposed to the laterally based flap. The knee that is most vulnerable to wound necrosis is one that has a prior long lateral incision followed by a parallel more medial incision ( Fig. 13-2 ). When the surgeon decides that a parallel incision is necessary, the bridge between the two incisions should be as wide as possible with a minimum bridge of 8 cm. Additionally, a lateral incision elevating a medial based flap for medial arthrotomy may be considered. In consideration of an arthritic knee in valgus, a lateral arthrotomy where the patella is everted medially should be seriously considered. When more than one incision is present, the most lateral that is usable should be used. Another alternative is to use the most recent incision that has successfully healed. In uncertain or problematic areas, the surgeon might consider the “sham” or “delayed incision.” The “sham” technique is a technique that was advocated by Dr. Frederick Ewald (personal communication). This type of incision involves making a skin incision and elevating the flaps in preparation for the arthrotomy. When using a tourniquet, it should be deflated or not inflated at all. Following this preparation, the medial and lateral skin edges should be inspected for any signs of active bleeding. If active bleeding is not present, the procedure should be terminated and consultation with a plastic surgeon should ensue.

The knee does not usually tolerate multiple parallel or crossing incisions.

Skin necrosis occurring after a medial incision was made parallel to an old lateral incision.

The “delayed incision,” advocated by Dr. John Insall (personal communication), begins like the “sham” technique with a skin incision being made, followed by elevation of the flaps for arthrotomy. The wound is then closed regardless of the clinical appearance. In the absence of any skin necrosis, the knee arthroplasty is then carried out 4 to 6 weeks later using the same incision site. The rationale behind the “delayed incision” is based on the assumption that the technique tests the viability of the skin flap, as well as promoting increased collateral circulation secondary to the healing process.

When tight adherent skin and subcutaneous tissue are present, tissue expanders have been used with excellent results. In severely scarred cases, the plastic surgery consultant may recommend a free flap transfer of muscle or fasciocutaneous tissue.

FIGURE 13-3 illustrates the most frequently encountered prior knee incisions, including diagrams of approaches most likely to be used in each case.

A: A short oblique medial incision can be extended to a longer median para-patellar incision. B. In a prior long oblique medial incision only the distal half is utilized. C. Transverse old incisions can usually be ignored. D. A prior short oblique “Coventry” incision can usually be ignored. E. After a short oblique prior lateral arthrotomy, the incision should be shifted medially to widen the skin bridge. F. A long prior lateral para-patellar must be respected and utilized.

WHAT TO DO FOR SKIN NECROSIS

In the presence of skin necrosis, it is vitally important to keep the skin sealed for as long as possible to allow the capsular incision to heal. To aid in this process, all range-of-motion exercises are halted and immobilization of the knee is recommended. The knee splint should be easily removable to allow for daily inspection of the wound site. After a 10-day period, the size of necrosis should be assessed and range of motion can commence. If necrosis is going to be a problem, this 10-day period will allow ample time for the necrosis to declare itself. When drainage from around the area of necrosis does not slow or cease within several days, consultation with a plastic surgeon for immediate intervention is necessary.

Several other options exist for treatment of skin necrosis about a TKA. When the area of skin necrosis is small and dry, the site can be left to granulate beneath the eschar. On the other hand, if the area is relatively small and the skin is pliable, the area can be excised and closed primarily. Once the joint capsule has sealed, the area can be excised and a split-thickness skin graft can be used. However, if the necrotic area is extensive with an unsealed or exposed joint, a gastrocnemius muscle flap may be required followed by a split-thickness skin graft. Alternately, a free tissue transfer may be required.

On occasion, patellectomy has allowed resolution of the skin necrosis problem in patients with severe preoperative deformities where extensive lateral release has been performed with sacrifice of the lateral genicular vessels. In these patients, bone scan has shown no uptake in the patella, indicating the site to be avascular. The patella is always greater than 2 cm thick; therefore, removing it should provide sufficient laxity in the capsule and the skin, allowing for primary closure of both layers.

THE DRAINING WOUND

Following a TKA, wound drainage should not be tolerated. On the second postoperative day, the operative dressing is changed and the site should be inspected for gaps in the skin closure. If any gaps are observed, the skin should be cleaned with povidone-iodine and alcohol. After cleaning the incision area, benzoin is applied along the edges of the incision and Steri-Strips are applied to reseal the wound. This process is repeated, typically for another 1 or 2 days, until the wound is dry for 24 hours. If drainage persists, treatment should be aggressive and the patient should be returned to the operating room for wound debridement irrigation and primary closure.

To ensure that the drainage does not represent a deep problem, aspiration of the knee joint through a remote site may be indicated. When this is done, the fluid is then sent to the laboratory for cell count, differential, and aerobic and anaerobic cultures. When in the operating room, the knee area is sterily prepped and draped. The surgeon will then remove two or three sutures from the area surrounding the drainage and a subcutaneous culture is obtained. If indicated, the skin edges are then freshened by removing 1 or 2 mm of tissue, skin is then closed with nylon sutures. Following this procedure, flexion exercises are suspended for 1 or 2 days until evidence indicates that the wound is healed.