Keywords

1 Introduction

For indications for radial head replacement, refer to Chap. 1.

Over the recent decades, radial head implants have evolved significantly with advances in materials, shapes, “implant-capitellum” loading (Table 79.1), and stem fixation.

Table 79.1 Comparison of unipolar and bipolar prostheses
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2 Indications/Contraindications

Indications and contraindications of radial head replacement, with possible alternative surgical treatments, are presented in Table 79.2.

Table 79.2 Radial head fractures
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2.1 Surgical Technique

A lateral approach is performed. If the medial side also needs to be approached, then either a common posterior approach or a combined approach (lateral and medial) should be used. The lateral approach can be a Kaplan, Kocher, or Wrightington approach (Fig. 79.1).

Fig. 79.1
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(a) The surgical approaches for radial head prosthesis (from top: Kaplan, Kocher, and Wrightington approaches). (b) Relationship between surgical approaches, PIN, and LUCL

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We prefer the Kocher approach, developing the interval between anconeus and extensor carpi ulnaris. The joint capsule is incised, remaining anterior to the radial head to preserve the main lateral stabilizer: the lateral ulnar collateral ligament (LUCL). The annular ligament and joint capsule are divided and the radial head is exposed.

If the fracture cannot be fixed, all the bony fragments are removed and the radial neck is resected with a saw. The bony fragments of the radial head are recreated on the back table, to confirm that all the fragments have been excised and to determine the size of the implant [1].

The intramedullary canal is exposed, with a Hohmann retractor on the posterior aspect of the radial neck and applying a varus and supination stress (Fig. 79.2). Placing a Hohmann retractor anteriorly is discouraged, as it may risk the PIN. Rasp the canal of the proximal radius and insert trial components.

Fig. 79.2
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Intraoperative view showing anterior langenbeck right angle retractor and the posterior typical retractors placement

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Fig. 79.3
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Prosthesis design (a) impingement points with standard prosthesis, especially in case of intact LUCL. (b, c) Sliding system for side loading simplifies the implant insertion

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Choosing the correct head size is critical [2]. To select the right head size, we suggest five tips (Tables 79.3 and 79.4).

Table 79.3 Five tips to choose the size of the radial head
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Table 79.4 Five tips to implant the stem
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Fig. 79.4
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Correct position of a radial head prosthesis at (a) 1-month (b) and 7-year follow-up. Suture anchor repair of the torn LUCL

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Fig. 79.5
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Radial head sizing. (a) Radial head recreated on the back table. (b, c) Specific sizing device for radial head

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3 Tips/Tricks

4 Postoperative Management, Rehabilitation, Return to Sport

The postoperative management is tailored to the elbow joint stability and the associated injuries.

5 Stable Elbow

  • Protective brace for 2–3 weeks.

  • Early mobilization, with an articulated brace or removing a non-articulated brace.

6 Slightly Unstable with Posterolateral Rotatory Instability

  • The elbow is protected in a 90° brace with the forearm in pronation.

  • Active overhead mobilization allowed after 3–7 days.

  • Avoid varus stress on the elbow.

In literature it is not possible to find any details regarding the return to sport after radial head arthroplasty. In our clinical practice, we discourage sport that causes high stresses on the radio-humeral joint (i.e., weight lifting and boxing).

7 Radial Head Arthroplasty Complications

The most recurrent complications are the following:

Loosening: Radiolucent lines around the stem are frequently seen in loose-fit prosthesis and, less often, in press-fit stem. Radiolucent lines are often asymptomatic and do not concern (Fig. 79.8). Therefore, it is important to distinguish them from loosening of the implant (Fig. 79.9).

Fig. 79.6
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Radial head trials. (a, b) Fluoroscopic and clinical comparison of two different sizes of radial head implants. Fluoroscopy shows that smaller diameter is similar to the native radial head

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Fig. 79.7
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Relationship between the normal radial head and lesser sigmoid notch

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Fig. 79.8
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Radiolucent lines around the stem have no progression at 5-year follow-up and are clinically asymptomatic

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Fig. 79.9
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Stem mobilization. (a) Inadequate radial neck. (b) Loose stem

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Fig. 79.10
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Overstuffed prosthesis with capitellar erosion: (a, b) radiographs; (c, d) CT image; (e) intraoperative photo with capitellar erosion

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Overstuffing: It is one of the most frequent complications after radial head arthroplasty. On the anteroposterior X-ray it can be found as asymmetric humero-ulnar joint space, widening on the radial side (delta river sign) (Fig. 79.10a, b). With the CT scan it is possible to compare the prosthesis length to the lesser sigmoid notch [3]. In the sagittal view a loss of symmetry between the humeral center of rotation and the olecranon and coronoid confirms the overlengthening of the radial head (Fig. 79.10c, d).

Capitellar erosion: It is usually due to prosthesis overstuffing (Fig. 79.10e) or longitudinal instability (Essex-Lopresti).

Nerve lesions: The most frequently damaged nerve is the PIN. To prevent these iatrogenic lesions, we suggest:

  • Do not use a Hohmann retractor on the anterior radial neck.

  • Pronate the forearm while exposing the radial neck, to keep the PIN anterior.

  • Avoid tissue dissection beyond the biceps tuberosity of the radius.

Osteoarthritis: Arthritis of the capitellum is usually the consequence of post-traumatic cartilage lesions. This can deteriorate if there is instability or increased pressure from the prosthesis.

Stiffness and heterotopic ossification: Postoperative stiffness can be caused by capsular contracture, osteoarthritis, HO, or ulnar neuropathy.

8 Results

A recent systematic review of >700 metallic modular prosthesis highlights good results in a short and medium follow-up, without any implant being superior to another [4]. In our experience, we have not found any significant difference between monopolar and bipolar prosthesis [5].

There are few studies with a long follow-up and they suggest that good results achieved in the short term are maintained over time [1].

The percentage of implant failure is between 0 and 29% [4]. In our experience [5] the revision rate was 6% at 2-year follow-up. These results are maintained at 5-year follow-up (unpublished data).